It does look very unhappy.
If it is a nutrient problem, one symptom is "chlorosis between the veins". Many leaves are generally pale, except the veins seem to stay green longer.
BUT I forget what that means in terms of nutrients. Sorry!
Also I couldn't tell whether the yellowing was mostly the lower and older leaves, mostly young new top growth, or "generally some yellow everywhere".
Lack of mobile nutrients like N shows up first in older, lower leaves. The plant steals nitrogen from old parts to keep the new parts growing.
Lack of an IMMOBILE nutrient shows up first in new leaves and new growth becoming pale, lime-green, or yellow. The plants can't get enough, and can't move it around internally, so new growth has to do without.
It might have multiple problems that I can't guess -
- something eating the roots,
- something eating the leaves and injecting a plant disease
- other disease
- severe nutrient imbalance (bad pH or some excess nutrient making other nutrients unavailable)
- poor drainage rotting roots
- ???
